This is a multicenter, Phase III trial of IVIG in symptomatic, HIV- infected children between 3 months and 12 years of age. Eligible children are randomized to receive monthly infusions of IVIG or placebo: all children receive standard doses of oral zidovudine. Over the 100 week study period, rates of serious bacterial infections, tolerance of the drug regimens, and progression of HIV infection are assessed. Clinical, immunological, and virological outcomes will be compared.